The present invention relates to a silver halide color photosensitive material containing a non-dye-forming coupler capable of releasing photographically useful group and, more particularly, to a silver halide photosensitive material containing a novel non-dye-forming DIR coupler capable of forming an essentially colorless cyclized product and releasing a development inhibitor or its precursor by intramolecular nucleophilic substitution using a nitrogen atom of an aromatic amine-based developing agent, which is produced by a coupling reaction with an oxidized form of the aromatic amine-based developing agent, as a nucleophilic seed.
In the field of color photosensitive materials, it is known that the properties of photographic images greatly improve by releasing a photographically useful group silver imagewise at the same time a silver image is formed.
For example, a DIR coupler releases a development inhibitor by coupling with an oxidized form of a developing agent upon development, thereby achieving functions of, e.g., improving the graininess of a color image, improving the sharpness by an edge effect, and improving the color reproduction by diffusion of the inhibitor to other layers. These functions are described in detail in, e.g., U.S. Pat. No. 4,248,962 and Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-)5-313322.
As described above, DIR couplers contribute to improvements of the quality of a color image. However, these couplers release a development inhibitor or its precursor by coupling with an oxidized form of a developing agent and at the same form an azomethine dye or indoaniline dye. Therefore, these couplers sometimes have an unpreferable effect on the color reproduction of a color image or an adverse effect on the image stability. This is a large cause of limitations on the versatility, use amount, and molecular design of these functional couplers and on functions achieved by the couplers.
For example, a highly active DIR coupler is necessary to give a satisfactory interlayer effect from a green-sensitive layer to a blue-sensitive layer. Since, however, no high-activity DIR coupler for generating a magenta dye exists, a high-activity coupler for generating a yellow dye or cyan dye is used in a green-sensitive layer. These DIR couplers sometimes cancel the interlayer effect by their own color formation. Also, the use amount is restricted because color impurity may occur.
Instead of DIR compounds, color correcting colored couplers are sometimes used to obtain an apparent interlayer effect or to correct the hue of an unpreferable coupler. However, the use amount of these colored couplers is naturally limited by the suitability for a printer.
As means for solving these problems, couplers (non-dye-forming couplers) capable of releasing PUG (photographically useful groups including a development inhibitor) by coupling with an oxidized form of a developing agent without (essentially) forming a dye are described in, e.g., Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-)52-46817 and U.S. Pat. No. 4,315,070. Also, some couplers (flow couplers) release PUG by coupling with an oxidized form of a developing agent and at the same time form a dye, but this dye formed flows out into a processing solution during photographic processing. These couplers are described in, e.g., JP-B-1-52742, JP-A-4-356042, and JP-A-8-44011. However, the former non-dye-forming couplers have low coupling activity and are not stable enough. Also, a dye flowing out from the latter flow couplers pollute a processing solution. This is unpreferable when the recent progress of low-replenishment processing is taken into consideration.
As means for releasing PUG with no dye formation, a method using a redox reaction with an oxidized form of a developing agent is known. Examples are DIR-hydroquinones described in, e.g., JP-A-49-129536 and U.S. Pat. No. 4,377,643; DIR-aminophenols described in, e.g., JP-A-52-57828; p-nitrobenzyl derivatives described in, e.g., EP45129; and hydrazine derivatives described in, e.g., JP-A-8-211542. Unfortunately, compared to the functional couplers described above, these redox compounds generally have low stability with time in a sensitive material and are slow to release PUG after a redox reaction.